Energy gradient ion beam deposition of carbon overcoats on rigid disk media for magnetic recordings

ABSTRACT

In the energy gradient ion beam deposition technique of the present invention, the fabrication of the overcoat layer starts with a low energy ion beam to avoid magnetic layer implantation problems, followed by higher deposition energies where the higher energy atoms are implanted into the previously formed lower energy overcoat layer, rather than the magnetic layer. The energy gradient ion beam deposition process therefore results in a thin overcoat layer that is denser than a comparable layer formed by low energy magnetron sputtering, and which overcoat layer provides good mechanical and corrosion protection to the magnetic layer, without degrading the magnetic properties of the magnetic layer. Where a magnetic media hard disk of the present invention is utilized within a hard disk drive, the thinner overcoat layer allows the magnetic head of the disk drive to fly closer to the magnetic media layer, thereby facilitating an increase in the areal data storage density of the hard disk drive.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to protective layersfabricated upon magnetic layers of hard disk media, and moreparticularly to thin film diamond-like carbon protective layers.

[0003] 2. Description of the Prior Art

[0004] Standard magnetic media hard disks include a magnetic layer thatis covered by a protective overcoat layer. The overcoat layer isnecessary to provide both mechanical and corrosion protection for themagnetic layer, and typical prior art overcoat layers are composed of ahard, carbon based composition that is applied by a magnetron sputteringtechnique to a thickness of approximately 50 to 200 Å.

[0005] The ongoing efforts to increase the areal data storage density ofmagnetic disks have resulted in a need to reduce the thickness of theovercoat layer while increasing the hardness, or density of the overcoatlayer. It has been found that a typical magnetron sputtered overcoat ofbelow approximately 50 Å is not sufficiently hard, nor does it providesufficient corrosion protection to the magnetic layer, due to thegenerally low energy (approximately 10 eV) at which the carbon atoms aredeposited. Efforts to create a thin, hard, corrosion resistant overcoathave therefore been directed towards fabrication devices such as massselected ion beam deposition (MSIB), cathodic arc, laser plasmadeposition and plasma enhanced chemical vapor deposition (PECVD) whichproduce carbon atom deposition energies of 100 eV or more. While such100 eV deposited overcoat layers provide good mechanical and corrosionresistance properties, they also create deterioration problems for theunderlying magnetic layer. Specifically, at such high energies, thecarbon atoms, as well as other atoms such as nitrogen and hydrogen thatare often utilized in forming the overcoat layer, become implanted intothe magnetic layer to a significant depth. The implanted atoms canseriously degrade the magnetic properties of the magnetic layer withinits upper regions, thus resulting in degraded performance of a magneticdisk that is fabricated with an overcoat layer formed with prior arthigh energy carbon deposition techniques.

[0006] The present invention solves these prior art problems through theuse of an energy gradient ion beam deposition technique in which theimplanting of carbon overcoat ions into the magnetic layer is reduced.

SUMMARY OF THE INVENTION

[0007] In the energy gradient ion beam deposition technique of thepresent invention, the fabrication of the overcoat layer starts with alow energy ion beam to avoid magnetic layer implantation problems,followed by higher deposition energies where the higher energy atoms areimplanted into the previously formed lower energy overcoat layer, ratherthan the magnetic layer. The energy gradient ion beam deposition processtherefore results in a thin overcoat layer that is denser than acomparable layer formed by low energy magnetron sputtering, and whichovercoat layer provides good mechanical and corrosion protection to themagnetic layer, without degrading the magnetic properties of themagnetic layer. Where a magnetic media hard disk of the presentinvention is utilized within a hard disk drive, the thinner overcoatlayer allows the magnetic head of the disk drive to fly closer to themagnetic media layer, thereby facilitating an increase in the areal datastorage density of the hard disk drive.

[0008] It is an advantage of the magnetic media hard disk of the presentinvention that it is fabricated with a thinner overcoat layer.

[0009] It is another advantage of the magnetic media hard disk of thepresent invention that it is fabricated with a denser overcoat layer.

[0010] It is a further advantage of the magnetic media hard disk of thepresent invention that it is fabricated with a thinner, denser effectiveovercoat layer wherein minimal implantation of carbon ions into themagnetic media layer is found.

[0011] It is yet another advantage of the magnetic media hard disk ofthe present invention that it is fabricated with a thinner effectiveovercoat layer such that a greater areal data storage density can becreated with said disk.

[0012] It is an advantage of the magnetic media hard disk drive of thepresent invention that it includes one or more magnetic media hard disksof the present invention wherein the data storage within said disk driveis increased.

[0013] It is another advantage of the hard disk drive of the presentinvention that it includes one or more magnetic disks of the presentinvention having a thinner effective overcoat layer, such that the arealdata storage density of said hard disk drive may be increased.

[0014] It is an advantage of the fabrication process for a magneticmedia hard disk of the present invention that a thinner, denser overcoatlayer is fabricated with minimal carbon ion implantation into a magneticmedia layer of the hard disk.

[0015] It is another advantage of the fabrication process for a magneticmedia hard disk of the present invention that controlled deposition ofnitrogen ion species into the overcoat layer may be accomplished.

[0016] These and other features and advantages of the present inventionwill no doubt become apparent to those skilled in the art upon readingthe following detailed description which makes reference to the severalfigures of the drawings.

IN THE DRAWINGS

[0017]FIG. 1 is a side cross-sectional view depicting a prior artovercoat layer formed by magnetron sputtering fabrication techniques;

[0018]FIG. 2 is a side cross-sectional view of a prior art magnetic diskincluding an overcoat layer that is formed utilizing high energy carbonion beam fabrication techniques;

[0019]FIG. 3 is a graphical representation of the implantation of carbonions of various energy levels into a magnetic layer;

[0020]FIG. 4 is a side cross-sectional view depicting a magnetic diskhaving an overcoat layer that is fabricated utilizing the energygradient ion beam deposition technique of the present invention;

[0021]FIG. 5 is a graphical representation of the implantation of 100 eVcarbon ions into 20 Å carbon surface layers having different densities;and

[0022]FIG. 6 is a schematic top plan view of a hard disk drive includingthe magnetic disk of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] As is well known to those skilled in the art, a thin filmovercoat layer is fabricated upon the magnetic layer of a magnetic mediahard disk to provide mechanical and corrosion protection to the magneticlayer. FIG. 1 is a side cross-sectional view of a typical prior artmagnetic media hard disk 10 having such an overcoat. As depicted in FIG.1, the prior art hard disk 10 includes a disk substrate 14 thattypically has a plurality of thin film layers deposited thereon. Whilevarious types of prior art hard disks exist, with various numbers andcompositions of thin film layers, for the purposes of this disclosure, atypical prior art hard disk 10 can be said to include a at least oneunderlayer 18 formed upon the surface of the substrate 14, a magneticlayer 26 formed upon the underlayer 18, and an overcoat layer 30 formedupon the magnetic layer 26. As indicated above, the present invention isdirected to the features and relationships between the magnetic layer 26and the overcoat layer 30. In a typical prior art hard disk 10, themagnetic layer 26 is composed of a magnetic material, usually having aCoPtCr composition, that has a thickness of approximately 50 to 200 Å.The overcoat layer 30 is composed of diamond-like carbon (DLC) and isapplied utilizing a magnetron sputtering technique having a relativelylow application energy that is less than or equal to approximately 10eV, and the DLC layer 30 is deposited to a thickness of at leastapproximately 50 Å to 200 Å. It is significant that there is very littleimplantation of the sputtered carbon ions of the overcoat layer 30 intothe magnetic layer 26, due to the low ion energy level of the overcoatlayer fabrication technique.

[0024] To increase the hard disk data areal storage density, it isdesirable to write magnetic data bits closer together in the data track;that is, to increase the number of bits per inch (BPI). To accomplishthis, it is desirable to have the magnetic write head positioned closerto the magnetic layer, and decreasing the thickness of the overcoatlayer 30 is advantageous in this regard. However, it has been found thatif the thickness of the prior art low energy magnetron sputteredovercoat layer 30 is reduced to below approximately 50 Å, both themechanical protection and corrosion protection of the magnetic layer is25 adversely affected. A prior art approach to resolve this problem isto apply the overcoat layer 30 utilizing a higher energy ion beamfabrication technique, such that a denser overcoat layer is fabricatedthan is achieved in the low energy magnetron sputtering process. Wherethe overcoat layer is denser, a thinner layer will provide suitablemechanical and corrosion protection to the magnetic layer, and amagnetic hard disk 50 with such a prior art high deposition energy DLCovercoat layer is depicted in FIG. 2.

[0025] As depicted in FIG. 2, the prior art magnetic hard disk 50includes a substrate 14 upon which an underlayer 18 has been deposited,followed by a 200 Å thick magnetic layer 26. The layers 14, 18 and 26may be identical to those described above with regard to prior art harddisk 10, whereby identical identification numbers are used herein. A DLCovercoat layer 54 that is fabricated in a high energy fabricationprocess such as mass selected ion beam deposition (MSIB), cathodic arc,laser plasma deposition and plasma enhanced chemical vapor deposition(PECVD) is formed upon the magnetic layer 26. It has been observed thatsome of the high energy carbon ions that form the overcoat layer 54penetrate into the magnetic layer 26, forming an ion implanted upperportion 58 of the magnetic layer of approximately 10 Å to 20 Å, as shownby the cross hatched portion 58 of the magnetic layer 26.

[0026] A graphical representation of the implantation of carbon ions ofvarious energy levels into a magnetic layer is presented in FIG. 3. Morespecifically, FIG. 3 depicts an implantation profile 70 for 10 eV carbonions, wherein the vertical axis (I/I₀) represents the quantity of carbonions and the horizontal axis represents the implantation depth of thecarbon ions from the surface (zero) into the magnetic media layer whichis composed of a CoPtCr alloy. In like manner, graphical profile 74represents 50 eV carbon ions, graphical profile 78 represents 100 eVcarbon ions and graphical profile 82 represents 500 eV carbon ions. Asis seen in FIG. 3, the great majority of 10 eV carbon ions 70 aredeposited within the first 5 Å, and nearly all of the 10 eV carbon ionsare deposited within the first 8 Å of the magnetic layer. With regard to100 eV carbon ions 78, a significant portion thereof are deposited inexcess of 10 Å. Thus, the crosshatched portion 58 of magnetic layer 26of FIG. 2 may be generally as deep as 20 Å for the 100 eV carbon ions.

[0027] Significantly, the implanted carbon ions influence the magneticproperties of the magnetic layer portion 58 and degrade its performance.The degraded performance of the ion implanted upper portion 58 of themagnetic layer can be quite significant with regard to overall diskperformance, because the upper portion 58 of the magnetic layer 26contributes significantly to the performance characteristics of magneticdata bits that are written into the magnetic layer. Therefore, the highenergy overcoat layer 54 is thinner than the prior art low energymagnetron sputtered layer 30, while still providing good hardness andcorrosion resistance; but the magnetic performance properties of thehard disk 50 are somewhat degraded due to the implantation of carbonovercoat layer ions into the magnetic layer 26. The present inventionprovides an improvement in the prior art overcoat layer technologies byutilizing an ion deposition beam having an energy gradient, such thatcarbon ion implantation into the magnetic layer is minimized, while thedesired thinness and density of the DLC overcoat layer are achieved.

[0028] As depicted in FIG. 4, a magnetic media hard disk 100 of thepresent invention generally includes the substrate 14, underlayer 18 andmagnetic layer 26, as are generally known in the prior art and describedhereabove with regard to FIGS. 1 and 2 above, and a DLC overcoat layer108 of the present invention that is fabricated on top of the magneticlayer 26. In that the present invention relates generally to the DLCovercoat layer 108, magnetic media hard disks having other, differentand additional layers fabricated beneath the magnetic layer 26, as wellas various magnetic layer compositions are intended to be includedwithin the scope of the present invention.

[0029] As has been indicated above, the overcoat layer 108 of thepresent invention is thinner and denser than the low energy magnetronsputtered layer 30, and it is fabricated such that carbon ionimplantation into the magnetic layer 26 is minimized. To accomplishthis, the overcoat layer 108 is fabricated utilizing a device thatproduces an ion beam that has an ion deposition energy gradient.Specifically, the fabrication of the overcoat layer 108 is commencedwith the deposition of an initial overcoat layer portion 112 with a lowenergy ion beam, such as a 10 to 20 eV ion beam, which is generally theenergy level of the low energy magnetron sputtering process of the priorart, as depicted in FIG. 1. Thereafter, as the deposition of the initialovercoat layer portion 112 progresses, the overcoat layer 112 increasesin thickness upon the surface of the magnetic layer 26, and due to therelatively low deposition beam energy level, implantation of overcoatlayer ions into the magnetic layer 26 is minimized. After the initialovercoat layer thickness is deposited at the low energy level, theenergy level of the beam is increased to deposit an intermediateovercoat layer portion 116. The higher energy ions will penetrate moredeeply into the surface layer, as has been described hereabove withregard to prior art disk 50; however, because the initial surface layer112 has been formed of overcoat material, the higher energy overcoations penetrate only into the pre-existing initial overcoat layer portion112. Thus, as the build up of the intermediate overcoat layer portion116 progresses, the total overcoat layer generally both becomes thickerwith overcoat ions that remain on its surface, as well as denser withhigher energy overcoat ions that become implanted within the thicknessof the initial overcoat layer. Thereafter, a subsequent overcoat layerportion 118 may be deposited with a still higher ion beam energy level.Again, these higher energy overcoat ions penetrate into the surface ofthe overcoat layer 108. However, due to the thickness of the existingovercoat layer the high energy ions become implanted into both theinitial and intermediate overcoat layer portions and do not penetrateinto the magnetic layer 26. A typical DLC overcoat layer density of thepresent invention is between approximately 2.0 g/cm³ to approximately2.9 g/cm³.

[0030]FIG. 5 is a graphical representation of 100 eV carbon ionimplantation into a magnetic disk having surface layers depositedthereon. Specifically, the graphical profile 120 represents theimplantation of 100 eV carbon ions into a CoPtCr magnetic layer havingno surface layer deposited thereon, and it can be seen that profile 120is substantially identical to profile 78 of FIG. 3. Profile 124represents the 100 eV carbon ion implantation into a 20 Å aC:H surfacelayer having a density of 1.7 grams/centimeter. It can be seen that thegreat majority of the 100 eV carbon ions are deposited within the 20 Ådepth of the surface layer. Graphical profile 128 represents theimplantation of 100 eV carbon ions into a 20 Å IBD-C surface layerhaving a density of 2.2 grams/centimeter, wherein it is seen that nearlyall of the 100 eV carbon ions are implanted within the 20 Å IBD-Csurface layer. It is therefore to be understood from the graphicalrepresentations of FIG. 5 that a sufficiently dense surface layer willprevent the implantation of 100 eV carbon ions into the magnetic layerof a hard disk.

[0031] It is therefore to be generally understood that the energygradient of the ion beam is to be controlled in association with thethickness of the overcoat layer that is being fabricated, such that thehighest beam energy levels are utilized when the thickness of theovercoat layer is close to its desired thickness. In this ion beamenergy gradient fabrication process the higher energy ions becomepredominantly implanted into the pre-existing overcoat layer portion,thereby increasing its density, hardness and corrosion resistance,without adding significantly to its thickness, and implantation of ionsinto the magnetic layer is minimized. Additionally, it is known that theaddition of nitrogen ions into the DLC layer can have a positive effectupon its hardness and corrosion resistance. However, nitrogen ions canalso create significant problems if they become implanted into themagnetic layer. Therefore, in an alternative preferred embodiment of thepresent invention, the initial lower energy overcoat layer fabricationis conducted without nitrogen ions. Thereafter, when an initial lowenergy overcoat layer has been deposited, nitrogen ions are thenincluded within the higher energy ion beam, to also become implantedwithin the overcoat layer, rather than into the magnetic layer. Anitrogen enhanced DLC layer is thereby produced in which nitrogen ionimplantation into the magnetic layer is minimized.

[0032] The present invention has been implemented in a Circulus magneticmedia hard disk fabrication device. In this device, the DLC overcoatlayer is applied onto the magnetic layer of hard disks utilizing a radiofrequency (RF) discharge chamber, which creates an overcoat ion plasmafrom a gaseous source. In this device, a deposition rate ofapproximately 10 Å per second is achieved with appropriate input gasconcentrations and other control parameters as are well known to thoseskilled in the art.

[0033] To create a DLC overcoat layer of the present invention,acetylene gas was utilized as the carbon ion source. The chamber controlparameters were set such that the acetylene gas produced a carbon ionplasma that was directed to the magnetic layer of a hard disk disposedwithin the chamber. The disk was exposed to an ion beam energy ofapproximately 10 eV for approximately one second, resulting in aninitial carbon overcoat layer having a thickness of approximately 10 Å.Thereafter, the ion beam energy level was increased to approximately 50eV and the disk was exposed for an additional one second to add anintermediate overcoat layer portion 116, to create an overcoat layerhaving a thickness of approximately 19 Å. Thereafter, the ion beamenergy was increased to approximately 100 eV, and the disk was exposedto the ion beam for approximately one second, to produce a subsequentovercoat layer portion 118, such that the total overcoat layer 108 has athickness of approximately 25 Å. In an enhanced overcoat layerdeposition process, nitrogen gas can be mixed with the acetylene gas inthe second and third deposition energy level steps to create nitrogenions that are implanted into the overcoat layer. The concentration ofnitrogen can be increased as the energy level is increased to create anitrogen enhanced overcoat layer. A preferred concentration range ofnitrogen ions within the overcoat layer is from approximately 2 at. % toapproximately 20 at. %.

[0034] While the example provided hereabove demonstrates the use of athree step (10 eV, 50 eV, 100 eV) ion beam energy gradient, it is to beunderstood that the present invention can be practiced utilizing a twostep gradient, a multiple step gradient, and a smooth energy gradient.Additionally, ion beam energy levels in excess of 100 eV arecontemplated, although there appears to be little advantage to ion beamenergy levels in excess of approximately 100 eV. A general principal ofthe present invention is that the thickness of the DLC layer formed atlower energy levels be sufficient to capture the carbon and nitrogenions that become implanted at higher energy levels. With the use ofappropriate process parameters such as deposition rates and times, aswill be understood by those skilled in the art after having read thisdisclosure, the thickness and density of the overcoat layer can becontrolled. Preferred embodiments of the present invention have anovercoat thickness of from approximately 25 Å to approximately 100 Å,with a more preferred upper thickness range of approximately 60 Å, andwith a more preferred thickness of approximately 35 Å; the density ofthe overcoat is between approximately 2.0 g/cm³ to 2.9 g/cm³, and theoptional nitrogen concentration is from 2 at. % to 20 at. %

[0035] The magnetic disk of the present invention is designed forinstallation in a hard disk drive, and FIG. 6 is a schematic top planview of a hard disk drive 200 which includes at least one, and typicallya plurality, of magnetic disks 100 of the present invention. As depictedtherein, at least one magnetic head disk 100 is rotatably mounted upon amotorized spindle 204. A slider 208, having a magnetic head 212 disposedthereon, is mounted upon an actuator arm 216 to fly above the surface ofeach rotating hard disk 100, as is well known to those skilled in theart. The hard disk drive 200 of the present invention thus includesimproved features and manufacturing methods for the magnetic disk 100 ashave been described hereabove.

[0036] While the present invention has been shown and described withreference to certain preferred embodiments, it is to be understood thatthose skilled in the art will no doubt devise certain alterations andmodifications thereto which nevertheless include the true spirit andscope of the present invention. It is therefore intended that thefollowing claims cover all such alterations and modifications in formand detail that nevertheless include the true spirit and scope of thepresent invention.

What we claim is:
 1. A magnetic media hard disk, comprising: asubstrate; a magnetic layer; at least one underlayer being disposedbetween said substrate and said magnetic layer; an overcoat layer beingdisposed above said magnetic layer, said overcoat layer being comprisedof diamond-like carbon (DLC), and wherein carbon atoms of said DLC layerare generally implanted into said magnetic layer to a depth of less thanapproximately 10 Å, and wherein the density of said overcoat layer isbetween approximately 2.0 g/cm³ and approximately 2.9 g/cm³.
 2. Amagnetic disk as described in claim 1 wherein the thickness of saidovercoat layer is from approximately 25 Å to approximately 100 Å.
 3. Amagnetic disk as described in claim 1 wherein the thickness of saidovercoat layer is from approximately 25 Å to approximately 60 Å.
 4. Amagnetic disk as described in claim 1 wherein the thickness of saidovercoat layer is approximately 35 Å.
 5. A magnetic disk as described inclaim 1 wherein said overcoat layer includes nitrogen.
 6. A magneticdisk as described in claim 5 wherein said overcoat layer includesnitrogen in the range of approximately 2 at. % to approximately 20 at.%.
 7. A hard disk drive, comprising: at least one magnetic media harddisk being adapted for rotary motion upon a disk drive motor spindle; atleast one slider device having a slider body portion being adapted tofly over said magnetic media hard disk; a magnetic head being formed onsaid slider body for writing data to said magnetic media hard disk andreading data from said magnetic media hard disk; said magnetic mediahard disk, including: a substrate; a magnetic layer; at least oneunderlayer being disposed between said substrate and said magneticlayer; an overcoat layer being disposed above said magnetic layer, saidovercoat layer being comprised of diamond-like carbon (DLC), and whereincarbon atoms of said DLC layer are generally implanted into saidmagnetic layer to a depth of less than approximately 10 Å, and whereinthe density of said overcoat layer is between approximately 2.0 g/cm³and approximately 2.9 g/cm³.
 8. A hard disk drive as described in claim7 wherein the thickness of said overcoat layer is from approximately 25Å to approximately 100 Å.
 9. A hard disk drive as described in claim 7wherein the thickness of said overcoat layer is from approximately 25 Åto approximately 60 Å.
 10. A hard disk drive as described in claim 7wherein the thickness of said overcoat layer is approximately 35 Å. 11.A hard disk drive as described in claim 7 wherein said overcoat layerincludes nitrogen.
 12. A hard disk drive as described in claim 11wherein said overcoat layer includes nitrogen in the range ofapproximately 2 at. % to approximately 20 at. %.
 13. A process forfabricating a magnetic media hard disk comprising the steps of:fabricating a magnetic media layer upon a surface material of asubstrate; fabricating a diamond-like carbon (DLC) layer upon saidmagnetic layer, including the steps of: fabricating an initial thicknessDLC layer portion upon said magnetic layer utilizing a relatively lowion carbon beam energy; fabricating a subsequent thickness DLC layerportion upon said initial thickness DLC layer portion utilizing arelatively high carbon ion beam energy.
 14. A process for fabricating amagnetic media hard disk as described in claim 13 wherein saidrelatively low carbon ion beam energy is approximately 10 eV toapproximately 20 eV.
 15. A process for fabricating a magnetic media harddisk as described in claim 14 wherein said relatively high ion beamenergy is approximately 100 eV.
 16. A process for fabricating a magneticmedia hard disk as described in claim 13, including the further step offabricating an intermediate thickness DLC layer portion between saidinitial DLC layer portion and said subsequent DLC layer portion, whereinsaid intermediate thickness DLC layer portion is fabricated utilizing arelatively mid-range carbon ion beam energy between said relatively lowcarbon ion beam energy and said relatively high carbon ion beam energy.17. A process for fabricating a magnetic media hard disk as described inclaim 16 wherein said intermediate carbon ion beam energy isapproximately 50 eV.
 18. A process for fabricating a magnetic media harddisk as described in claim 17 wherein said DLC layer has a thickness ofapproximately 10 Å following the deposition of said initial thicknessDLC layer portion, and said DLC layer has a thickness of approximately19 Å following the deposition of said intermediate thickness DLC layerportion, and said DLC layer has a final thickness of approximately 25 Åfollowing the deposition of said subsequent thickness DLC layer portion.19. A method for fabricating a magnetic media hard disk as described inclaim 18 wherein said DLC layer is formed with a density ofapproximately 2.0 g/cm³ to approximately 2.9 g/cm³.
 20. A method forfabricating a magnetic media hard disk as described in claim 13 whereinnitrogen ion species are deposited within said subsequent thickness DLClayer portion.
 21. A process for fabricating a magnetic media hard diskas described in claim 20 wherein said nitrogen species are deposited ina range of approximately 2 at. % to approximately 20 at. %.
 22. A methodfor fabricating a magnetic media hard disk comprising the steps of:fabricating a magnetic material layer upon a material surface of asubstrate; fabricating a diamond-like carbon (DLC) layer upon saidmagnetic layer, wherein said DLC layer is fabricated in the steps of:depositing carbon ion species upon said magnetic layer utilizing arelatively low carbon ion beam energy of from approximately 10 eV toapproximately 20 eV, to deposit an initial DLC layer thickness;subsequently increasing the carbon ion beam energy level as thethickness of said DLC layer increases due to deposition of carbon ionspecies within said DLC layer, such that higher energy carbon ion beamspecies become implanted within said DLC layer thickness.
 23. A methodfor fabricating a magnetic media disk as described in claim 22 whereinsaid carbon ion beam energy level is varied smoothly with time.
 24. Amethod for fabricating a magnetic media hard disk as described in claim22 wherein said carbon ion beam energy level varies as a step functionwith time.
 25. A method for fabricating a magnetic media hard disk asdescribed in claim 23 wherein nitrogen ion species are implanted withinsaid DLC layer thickness.
 26. A method for fabricating a magnetic mediahard disk as described in claim 25 wherein said nitrogen ion species areincluded within said DLC layer in a range of approximately 2 at. % toapproximately 20 at. %.